1. Field of the Invention
The present invention relates to a coating structure for forming a tool, and especially relates to the design of plate materials combined with each other to replace the complicated forging process. Furthermore, an outer coating layer is covered on an outer surface of a tool body by injection molding so as to save cost.
2. Description of Related Art
Since the wrench tool must take higher torque, the steel materials must be selected more expensive materials and made by the base materials with better rigidity so that the cost is much higher. In addition, the manufacturing process is the forging molding and further includes complicated processes, such as straightening, cutting, heating, and so on. For example, the raw material after heating must be cooled for forging molding and then machining, such as lathe turning, drilling, to form an outlook of the wrench body. After heating for reinforcing the structure, it must be polished so as to make the surface of the wrench (tool) smooth and then electroplated to prevent from rusting. The whole process is complicated and makes the cost too high.
Furthermore, since the wrench has various sizes, the prices may be different based on the sizes of the wrench. The smaller the size is, and the lower the price is. Although the manufacturing processes are the same for the tools with various sizes and the equipment is not different, the small-size tools may be set to use in the manufacturing process. However, the changes of the small-size tools may be expired cost which is hard to control. For example, when heating, the small-size tool is easy to deform due to small size and structure. And the small-size tools after heating may be deformed over an angular of 180 degree. Therefore, the straightening process is much longer or added at least one more and the cost is increased. Besides, since the small-size tools after heating cannot be hanged stably and are easy to be deformed, they are dropped and deposited at the bottom of the furnace to result in defect rate higher. Therefore, the cost is hard to control.
In order to solve above mentioned problems, unless the twisting load is influenced in operation, there is an outer covering shell is designed to cover on the outer surface of the wrench tool. The steel material cost may be decreased to cost down.
However, a larger gap may be formed by the manner of covering the outer covering shell on the outer surface of the wrench tool between the outer covering shell and the wrench tool. The outer covering shell is hard to firmly fasten to the wrench tool. The vibration and slide may be resulted while in operation. It is inconvenient.
In addition, the complicated processes, including straightening, cutting, heating, and forging after molding, are not changed and the cost is still high. The material cost which is decreased by covering the outer covering shell on the outer surface of the wrench tool is not efficiently obvious.
In view of the foregoing circumstances, the inventor has invested a lot of time to study the relevant knowledge, compare the pros and cons, research and develop related products. After quite many experiments and tests, the “coating structure for forming a tool” of this invention is eventually launched to improve the foregoing shortcomings, to meet the public use.